psychologywikiaorg-20200213-history
Evolutionary psychology
Evolutionary psychology (EP) attempts to explain mental and psychological traits—such as memory, perception, or language—as adaptations, that is, as the functional products of natural selection or sexual selection. Adaptationist thinking about physiological mechanisms, such as the heart, lungs, and immune system, is common in evolutionary biology. Evolutionary psychology applies the same thinking to psychology. Most research in evolutionary psychology focuses on humans. Evolutionary psychologists argue that much of human behavior is generated by psychological adaptations that evolved to solve recurrent problems in human ancestral environments. They hypothesize, for example, that humans have inherited special mental capacities for acquiring language, making it nearly automatic, while inheriting no capacity specifically for reading and writing. Other adaptations, according to EP, might include the abilities to infer others' emotions, to discern kin from non-kin, to identify and prefer healthier mates, to cooperate with others, and so on. Consistent with the theory of natural selection, evolutionary psychology sees organisms as often in conflict with others of their species, including mates and relatives. For example, mother mammals and their young offspring sometimes struggle over weaning, which benefits mother more than the child. Humans, however, have a marked capacity for cooperation as well. Evolutionary psychologists see those behaviors and emotions that are nearly universal, such as fear of spiders and snakes, as more likely to reflect evolved adaptations. Evolved psychological adaptations (such a the ability to learn a language) interact with cultural inputs to produce specific behaviors (e.g., the specific language learned). This view is contrary to the idea that human mental faculties are general-purpose learning mechanisms. Fields closely related to EP are animal behavioral ecology, human behavioral ecology, dual inheritance theory, and sociobiology. Overview Evolutionary psychology (EP) is an approach to the entire discipline that views human nature as a universal set of evolved psychological adaptations to recurring problems in the ancestral environment. Proponents of EP suggest that it seeks to heal a fundamental division at the very heart of science --- that between the soft human social sciences and the hard natural sciences, and that the fact that human beings are living organisms demands that psychology be understood as a branch of biology. Anthropologist John Tooby and psychologist Leda Cosmides note: "Evolutionary psychology is the long-forestalled scientific attempt to assemble out of the disjointed, fragmentary, and mutually contradictory human disciplines a single, logically integrated research framework for the psychological, social, and behavioral sciences—a framework that not only incorporates the evolutionary sciences on a full and equal basis, but that systematically works out all of the revisions in existing belief and research practice that such a synthesis requires."Tooby & Cosmides 2005, p. 5 Just as human physiology and evolutionary physiology have worked to identify physical adaptations of the body that represent "human physiological nature," the purpose of evolutionary psychology is to identify evolved emotional and cognitive adaptations that represent "human psychological nature." EP is, to quote Steven Pinker, "not a single theory but a large set of hypotheses" and a term which "has also come to refer to a particular way of applying evolutionary theory to the mind, with an emphasis on adaptation, gene-level selection, and modularity." EP proposes that the human brain comprises many functional mechanisms,evolutionary psychology Psyche Games. Accessed August 22 2007 called psychological adaptations or evolved cognitive mechanisms or cognitive modules designed by the process of natural selection. Examples include language acquisition modules, incest avoidance mechanisms, cheater detection mechanisms, intelligence and sex-specific mating preferences, foraging mechanisms, alliance-tracking mechanisms, agent detection mechanisms, and other . EP has roots in cognitive psychology and evolutionary biology (See also sociobiology). It also draws on behavioral ecology, artificial intelligence, genetics, ethology, anthropology, archaeology, biology, and zoology. EP is closely linked to sociobiology, but there are key differences between them including the emphasis on domain-specific rather than domain-general mechanisms, the relevance of measures of current fitness, the importance of mismatch theory, and psychology rather than behaviour. Many evolutionary psychologists, however, argue that the mind consists of both domain-specific and domain-general mechanisms, especially evolutionary developmental psychologists. Most sociobiological research is now conducted in the field of behavioral ecology. The term evolutionary psychology was probably coined by American biologist Michael Ghiselin in a 1973 article published in the journal Science. Jerome Barkow, Leda Cosmides and John Tooby popularized the term "evolutionary psychology" in their highly influential 1992 book The Adapted Mind: Evolutionary Psychology and The Generation of Culture. EP has been applied to the study of many fields, including economics, aggression, law, psychiatry, politics, literature, and sex. EP uses Nikolaas Tinbergen's four categories of questions and explanations of animal behavior. Two categories are at the species level; two, at the individual level, as noted in the table below. The species-level categories (often called “ultimate explanations”) are *the function (i.e., adaptation) that a behavior serves and *the evolutionary process (i.e., phylogeny) that resulted in the adaptation (functionality). The individual-level categories are *the development of the individual (i.e., ontogeny) and *the proximate mechanism (e.g., brain anatomy and hormones). Evolutionary psychology mostly focuses on the adaptation (functional) category. Principles Evolutionary psychology is a hybrid discipline that draws insights from modern evolutionary theory, biology, cognitive psychology, anthropology, economics, computer science, and paleoarchaeology. The discipline rests on a foundation of core premises. According to evolutionary psychologist David Buss, these include: # Manifest behavior depends on underlying psychological mechanisms, information processing devices housed in the brain, in conjunction with the external and internal inputs that trigger their activation. # Evolution by selection is the only known causal process capable of creating such complex organic mechanisms. # Evolved psychological mechanisms are functionally specialized to solve adaptive problems that recurred for humans over deep evolutionary time. # Selection designed the information processing of many evolved psychological mechanisms to be adaptively influenced by specific classes of information from the environment. # Human psychology consists of a large number of functionally specialized evolved mechanisms, each sensitive to particular forms of contextual input, that get combined, coordinated, and integrated with each other to produce manifest behavior. Similarly, pioneers of the field Leda Cosmides and John Tooby consider five principles to be the foundation of evolutionary psychology: # The brain is a physical system. It functions as a computer with circuits that have evolved to generate behavior that is appropriate to environmental circumstances # Neural circuits were designed by natural selection to solve problems that human ancestors faced while evolving into Homo sapiens # Consciousness is a small portion of the contents and processes of the mind; conscious experience can mislead individuals to believe their thoughts are simpler than they actually are. Most problems experienced as easy to solve are very difficult to solve and are driven and supported by very complicated neural circuitry # Different neural circuits are specialized for solving different adaptive problems. # Modern skulls house a stone age mind. Evolutionary psychology is founded on the computational theory of mind, the theory that the mind, our "inner world," is the action of complex neural structures in the brain. For example, when a child shrinks in fear from a spider, the child's brain has attended to the spider, computed that it's a potential threat, and initiated a fear response. General evolutionary theory : Main article: Evolution Evolutionary psychology is rooted in evolutionary theory. It is sometimes seen not simply as a sub-discipline of psychology but as a way in which evolutionary theory can be used as a meta-theoretical framework within which to examine ''the entire field of psychology. A few biologists challenge the basic premises of evolutionary psychology.See for example: illustrations of beak variation in the finches of the Galápagos Islands.]] Natural selection Natural selection, a key component of evolutionary theory, involves three main ingredients: * Genetically based inheritance of traits - some traits are passed down from parents to offspring in genes, * Variation - heritable traits vary within a population (now we know that mutation is the source of this genetic variation), * Differential survival and reproduction - these traits will vary in how strongly they promote the survival and reproduction of their bearers. Selection refers to the process by which environmental conditions "select" organisms with the appropriate traits to survive; these organisms will have such traits more strongly represented in the next generation. This is the basis of adaptive evolution. Darwin's great claim was that this "natural selection" was creative - it could lead to new traits and even new species, it was centred on individual survival, and it could explain the broad scale patterns of evolution. Sexual selection Many traits that are selected for can actually hinder survival of the organism while increasing its reproductive opportunities. Consider the classic example of the peacock's tail. It is metabolically costly, cumbersome, and essentially a "predator magnet." What the peacock's tail does do is attract mates. Thus, the type of selective process that is involved here is what Darwin called "sexual selection." Sexual selection can be divided into two types: * Intersexual selection, which refers to the traits that one sex generally prefers in the other sex, (e.g. the peacock's tail). * Intrasexual competition, which refers to the competition among members of the same sex for mating access to the opposite sex, (e.g. two stags locking antlers). Inclusive fitness Inclusive fitness theory, which was proposed by William D. Hamilton in 1964 as a revision to evolutionary theory, is basically a combination of natural selection, sexual selection, and kin selection. It refers to the sum of an individual's own reproductive success plus the effects the individual's actions have on the reproductive success of their genetic relatives. General evolutionary theory, in its modern form, is essentially inclusive fitness theory. Inclusive fitness theory resolved the issue of how "altruism" evolved. The dominant, pre-Hamiltonian view was that altruism evolved via group selection: the notion that altruism evolved for the benefit of the group. The problem with this was that if one organism in a group incurred any fitness costs on itself for the benefit of others in the group, (i.e. acted "altruistically"), then that organism would reduce its own ability to survive and/or reproduce, therefore reducing its chances of passing on its altruistic traits. Furthermore, the organism that benefited from that altruistic act and only acted on behalf of its own fitness would increase its own chance of survival and/or reproduction, thus increasing its chances of passing on its "selfish" traits. Inclusive fitness resolved "the problem of altruism" by demonstrating that altruism can evolve via kin selection as expressed in Hamilton's rule: ::::cost < relatedness × benefit In other words, altruism can evolve as long as the fitness cost of the altruistic act on the part of the actor is less than the degree of genetic relatedness of the recipient times the fitness benefit to that recipient. This perspective reflects what is referred to as the gene-centered view of evolution and demonstrates that group selection is a very weak selective force. However, in recent years group selection has been making a comeback, (albeit a controversial one), as multilevel selection, which posits that evolution can act on many levels of functional organization, (including the "group" level), and not just the "gene" level. Foundations Source: Mills, M.E. (2004). Evolution and motivation. Symposium paper presented at the Western Psychological Association Conference, Phoenix, AZ. April, 2004. Middle-level evolutionary theories Middle-level evolutionary theories are theories that encompass broad domains of functioning. They are compatible with general evolutionary theory but not derived from it. Furthermore, they are applicable across species. During the early 1970s, three very important middle-level evolutionary theories were contributed by Robert Trivers: * The theory of reciprocal altruism explains how altruism can arise amongst non-kin, as long as there is a sufficient probability of the recipient of the altruistic act reciprocating at a later date. The possibility was also noted by Trivers, later coined 'indirect altruism' by Richard D. Alexander, that reciprocation could be provided by third parties, raising the issue of social reputation. * Parental investment theory refers to the different levels of investment in offspring on the part of each sex. For example, females in any species are defined as the sex with the larger gamete. In humans, females release approximately one large, metabolically costly egg per month, as opposed to the millions of relatively tiny and metabolically cheap sperm that are produced each day by males. Females are fertile for only a few days each month, while males are fertile every day of the month. Females also have a nine month gestation period, followed by a few years of lactation. Males' obligatory biological investment can be achieved with one copulatory act. Consequently, human females have a significantly higher obligatory investment in offspring than males do. (In some species, the opposite is true.) Because of this difference in parental investment between males and females, the sexes face different adaptive problems in the domains of mating and parenting. Therefore, it is predicted that the higher investing sex will be more selective in mating, and the lesser investing sex will be more competitive for access to mates. Thus, differences in behaviour between sexes is predicted to exist not because of maleness or femaleness per se, but because of different levels of parental investment. * The theory of parent-offspring conflict rests on the fact that even though a parent and his/her offspring are 50% genetically related, they are also 50% genetically different. All things being equal, a parent would want to allocate their resources equally amongst their offspring, while each offspring may want a little more for themselves. Furthermore, an offspring may want a little more resources from the parent than the parent is willing to give. In essence, parent-offspring conflict refers to a conflict of adaptive interests between parent and offspring. However, if all things are not equal, a parent may engage in discriminative investment towards one sex or the other, depending on the parent's condition. Additional middle-level evolutionary theories used in EP include: *The Trivers-Willard hypothesis, which proposes that parents should invest more in the sex that gives them the greatest reproductive payoff (grandchildren) with increasing or marginal investment. Females are the heavier parental investors in our species. Because of that, females have a better chance of reproducing at least once in comparison to males. Thus, according to the Trivers-Willard hypothesis, parents in good condition are predicted to favor investment in sons, and parents in poor condition are predicted to favor investment in daughters. *'r/K selection theory', which, in ecology, relates to the selection of traits in organisms that allow success in particular environments. r-selected species, (in unstable or unpredictable environments), produce many offspring, each of which is unlikely to survive to adulthood, while K-selected species, (in stable or predictable environments), invest more heavily in fewer offspring, each of which has a better chance of surviving to adulthood. *'Evolutionary game theory', the application of population genetics-inspired models of change in gene frequency in populations to game theory. *'Evolutionary stable strategy', which refers to a strategy, which if adopted by a population, cannot be invaded by any competing alternative strategy. Evolved psychological mechanisms Evolutionary psychology is based on the belief that, just like hearts, lungs, livers, kidneys, and immune systems, cognition has functional structure that has a genetic basis, and therefore has evolved by natural selection. Like other organs and tissues, this functional structure should be universally shared amongst a species, and should solve important problems of survival and reproduction. Evolutionary psychologists seek to understand psychological mechanisms by understanding the survival and reproductive functions they might have served over the course of evolutionary history. While philosophers have generally considered human mind to include broad faculties, such as reason and lust, evolutionary psychologists describe EPMs as narrowly evolved to deal with specific issues, such as catching cheaters or choosing mates. Some mechanisms, termed domain-specific, deal with recurrent adaptive problems over the course of human evolutionary history. Domain-general mechanisms, on the other hand, deal with evolutionary novelty. Environment of evolutionary adaptedness EP argues that to properly understand the functions of the brain, one must understand the properties of the environment in which the brain evolved. That environment is often referred to as the environment of evolutionary adaptedness, or EEA for short. Definition The term environment of evolutionary adaptedness was coined by John Bowlby as part of attachment theory. It refers to the environment to which a particular evolved mechanism is adapted. More specifically, the EEA is defined as the set of historically recurring selection pressures that formed a given adaptation, as well as those aspects of the environment that were necessary for the proper development and functioning of the adaptation. In the environment in which ducks evolved, for example, attachment of ducklings to their mother had great survival value for the ducklings. Because the first moving being that a duckling was likely to see was its mother, a psychological mechanism that evolved to form an attachment to the first moving being would therefore properly function to form an attachment to the mother. In novel environments, however, the mechanism can malfunction by forming an attachment to a dog or human instead. Human EEA Humans, comprising the genus Homo, appeared between 1.5 and 2.5 million years ago, a time that roughly coincides with the start of the Pleistocene 1.8 million years ago. Because the Pleistocene ended a mere 12,000 years ago, most human adaptations either newly evolved during the Pleistocene, or were maintained by stabilizing selection during the Pleistocene. Evolutionary psychology therefore proposes that the majority of human psychological mechanisms are adapted to reproductive problems frequently encountered in Pleistocene environments. In broad terms, these problems include those of growth, development, differentiation, maintenance, mating, parenting, and social relationships. To properly understand human mating psychology, for example, it is essential to recognize that in the EEA (as now) women got pregnant and men did not. Mismatches If humans are mostly adapted to Pleistocene environments, then some psychological mechanisms should occasionally exhibit “mismatches” to the modern environment, similar to the attachment patterns of ducks. One example is the fact that although about 10,000 people are killed with guns in the US annually,CDC pdf whereas spiders and snakes kill only a handful, people nonetheless learn to fear spiders and snakes about as easily as they do a pointed gun, and more easily than an unpointed gun, rabbits or flowers. A potential explanation is that spiders and snakes were a threat to human ancestors throughout the Pleistocene, whereas guns (and rabbits and flowers) were not. There is thus a mismatch between our evolved fear learning psychology and the modern environment. Research methods Evolutionary psychologists use several methods and data sources to test their hypotheses, as well as various comparative methods to test for similarities and differences between: humans and other species, males and females, individuals within a species, and between the same individuals in different contexts. They also use more traditional experimental methods involving, for example, dependent and independent variables. Evolutionary psychologists also use various sources of data for testing, including archeological records, data from hunter-gather societies, observational studies, self-reports, public records, and human products. Controversies Applying evolutionary theory to animal behavior is uncontroversial. However, adaptationist approaches to human psychology are contentious, with critics questioning the scientific nature of evolutionary psychology, and with more minor debates within the field itself. Criticisms of the field have also been addressed by scholars. ; in Criticisms Journals *[[:Category:Evolutionary psychology journals] **''Evolution and Human Behavior'' See also * Behavioural genetics * Dual inheritance theory * Evolution of sexual reproduction * Evolutionary developmental psychology * Evolutionary educational psychology * Gene-centered view of evolution * Human behavioral ecology * List of evolutionary psychologists * Evolutionary Psychology Research Groups and Centers * Evolutionary neuroscience Notes References * * * * * * * *Ploeger, A., van der Maas, H.L., Raijmakers, M.E. (2008). Is Evolutionary Psychology a Metatheory for Psychology? A Discussion of Four Major Issues in Psychology From an Evolutionary Developmental Perspective. Psychological Inquiry, Vol. 19, No. 1. pp. 1-18. * * * Further reading See: *Bibliography of evolution and human behavior * Buss, D. M. (1995). Evolutionary psychology: A new paradigm for psychological science. Psychological Inquiry, 6, 1-30. Full text * Durrant, R., & Ellis, B.J. (2003). Evolutionary Psychology. In M. Gallagher & R.J. Nelson (Eds.), Comprehensive Handbook of Psychology, Volume Three: Biological Psychology (pp. 1-33). New York: Wiley & Sons. Full text * Tooby, J. & Cosmides, L. (2005). Conceptual foundations of evolutionary psychology. In D. M. Buss (Ed.), The Handbook of Evolutionary Psychology (pp. 5-67). Hoboken, NJ: Wiley. Full text * For more readings, see the books page at the Human Behavior and Evolution Society External links * Evolutionary Psychology page at Scholarpedia * * Evolutionary Psychology page at Citizendium *What Is Evolutionary Psychology? by Clinical Evolutionary Psychologist Dale Glaebach. Academic societies * Human Behavior and Evolution Society; international society dedicated to using evolutionary theory to study human nature * The International Society for Human Ethology; promotes ethological perspectives on the study of humans worldwide * The Association for Politics and the Life Sciences; international and interdisciplinary association concerned with evolutionary, genetic and ecological knowledge * Society for Evolutionary Analysis in Law * The New England Institute for Cognitive Science and Evolutionary Psychology * The NorthEastern Evolutionary Psychology Society; regional society dedicated to encouraging scholarship and dialogue on the topic of evolutionary psychology] Journals * Evolutionary Psychology * The Journal of Social, Evolutionary & Cultural Psychology * Evolution and Human Behavior; journal of the Human Behavior and Evolution Society * Biological Theory: Integrating Development, Evolution and Cognition; publishes theoretical advances in the fields of biology and cognition, emphasizing the conceptual integration afforded by evolutionary and developmental approaches. Free access to Winter 2006 issues Important publications *List of important publications in psychology#evolutionary psychology Videos *Brief video clip re what EP is (from the "Evolution" PBS Series) *Margaret Mead and Samoa; review of the nature vs. nurture debate triggered by Coming of Age in Samoa *Video interview with Steven Pinker by Robert Wright (journalist) discussing evolutionary psychology *Video interview with Edward O. Wilson by Robert Wright (journalist), contextualizing evolutionary psychology within science, politics, academics and philosopy Category:Branches of psychology psychology Category:Evolutionary psychology Category:Interdisciplinary fields Category:Psychology